Abstract: In daily production, more and more small faults and small accidents occurred in periodlevel; and the current distributed control system has not effective method to record the periodlevel signals. The OVATION system manufactured by Emerson provides a special algorithm, SoftSOE, to record the periodlevel accidents. The application of SoftSOE in a power plant shows that by using the SoftSOE technology, the accident analysis measure was enhanced greatly, and the safety of the unit increased vastly.

Key words: record of sequence of event (SOE), period-level, SoftSOE